1. 直接写出得数

2+9=         7+5=          10+8=        6+9=

5+8=         4+8=           16–6=      9–5=

7+8 =         3+7=           9+4=         14+5=

6+8 =         5+9=           9+9=         18–6=

18–7+4=        17+2–6=       18–3–2=

19–5–5=         16–2-1=        3+5+9=